The invention relates to a contact arrangement in a relay for high breaking capacity comprising a movable contact spring which is split in fork-like fashion into two ends at its free end. Each of these fork ends is opposite a stationary cooperating contact element at at least one side.
Such a relay is disclosed, for example, by German Utility Model No. 81 34 890, corresponding to U.S. Ser. No. 433,837, filed Oct. 12, 1982, incorporated herein by reference. In general terms, contact springs having split ends for double contacting have been standard for a long time in order, for example, to enhance the contact reliability, given weak current contacts. Given relays with which high powers are switched, a contact spring having double contacts serves either as a bridge contact without its own terminal, or the current path is divided via two contacts as a parallel circuit in order to divide the high switching current onto the conductive cross-section of two terminal elements, and to thus protect these against excessive heating. In both of these instances, however, the contact arrangements have hitherto been designed such that the full switching current flows over the spring. In order to keep the voltage drop and the heating low, the contact spring must therefore be formed of material having good electrical conductivity. On the other hand, such a spring must also exhibit defined elastic properties in order to guarantee the required switching characteristic and the contacting forces. In order to meet all of these demands, thus the contact spring must be produced of an expensive copper alloy.
Given simple contacts, it has in fact been known to directly conduct the current from a terminal element to the contact location via a stranded copper conductor, whereby the stranded copper conductor was directly connected to the contact member (German UM No. 81 09 089 and German Pat. No. 29 27 879, both incorporated herein by reference). For a contact spring comprising an end split in fork-like fashion wherein each of these ends carries a contact member, this known type of direct contacting would mean twice the expense.